Oil Pools Research Articles

Effect of foam air mixing on flame intensification -- comparative experimental study of foam and water sprays extinguishing transformer oil pool fire

In this paper, the mechanism of flame intensification during the suppression of transformer oil pool fire is investigated for foam and water sprays. The results show that the extinguishment time is proportional to the discharge height and inversely proportional to the discharge pressure because greater height or lower pressure reduces the amount of suppression agent reaching the fuel bed thus extending extinguishment time. The increase of heat release rate following activation is inversely proportional to the discharge height and directly proportional to the discharge pressure; again, affected by the amount of suppression agent. When the nozzle is above the flame, the foam spray is affected by the entrapped air within, resulting in greater flame intensification, which is 3.5 times compared to water spray. For radiation, when the nozzle is above the flame, the heat flux increase is inversely proportional to the discharge pressure, which differs from the relationship for heat release rate increase. This difference is due to the shielding effect of the blanketing spray. For predict the heat release rate increase, an empirical model is developed, and an air mixing coefficient, τ, is introduced for foam spray to account for a 20%–35% increase in the heat release rate.

Soybean Based Cropping Systems in Central India: Production Growth and Instability Analysis

Aim: Soybean is one of the most substantial contributors to the Indian edible oil pool and Madhya Pradesh is its dominant contributor necessities the study on growth and instability of soybean based cropping systems including wheat and chickpea as Rabi crop in the system in Madhya Pradesh.
 Study and Design: The estimates of compound growth rate and instability were worked out for the period of 32 years (1988-89 to 2019-20).
 Place and Duration of Study: The study was conducted in nine major soybean growing districts having more than 75 percent Kharif cropped area under soybean crop including Bhopal (84%), Sehore (82%), Rajgarh (82%), Indore (91%), Ujjain (98%), Mandsaur (78%), Ratlam (79%), Shajapur including Aagar Malwa (95%) and Harda (75%) were purposively selected for the present study of Madhya Pradesh state by taking wheat and gram as Rabi crop in the system.
 Methodology: The exponential trend equation was used to estimate the compound growth rate. Using the Cuddy Della Valle Instability Index (CDVI) the risk was estimated for the soybean crop's area, production, and productivity.
 Results: The results of the study reveal that in the state of Madhya Pradesh positive and significant growth rate in the area, production, and productivity of soybean based cropping systems i.e. soybean, wheat after soybean, and chickpea after soybean were observed. On the contrary growth in productivity of soybean was positive but it is insignificant. Most of the selected districts also lie in low instability zone for production components of soybean based cropping systems.
 Conclusion: Approximately 30 per cent of the soybean production in the state was in the range of low range of production growth with low to medium instability. The lower production growth was mainly due to insignificant growth in productivity in mentioned districts. Thus, major emphasis should be given to increasing the productivity of soybean by an improved package of practices along with recommended variety according to an agro-climatic situation.

Influence of Water Mist Nozzle Characteristic Parameters on Oil Pool Fire Extinguishing in Confined Space

Influence of Water Mist Nozzle Characteristic Parameters on Oil Pool Fire Extinguishing in Confined Space

Influence of Water Mist Temperature Approach on Fire Extinguishing Effect of Different Pool Fires

The aim of this paper was to study the suppression influence of water mist on oil pool fires, taking diesel fires and n-heptane fires as experimental objects. The effects of spray pressure and temperature on water mist suppression were examined, and an experimental platform for the suppression of water mist in a small space was set up. Their fire prevention performance and fire extinguishing mechanisms were analyzed by comparing the flame temperature and extinguishing time of diesel and n-heptane pool fire. Three types of spray pressure were set. Water mist was designed at different temperatures and design experiments were carried out for this purpose. The change process of smoke concentration, thermocouple temperature, and flame combustion under different working conditions were analyzed, and the factors affecting the fire extinguishing effect of water mist on oil pool fire were discussed. The results show that 20 °C water mist is more effective at medium and high pressure than at low pressure. Moreover, 80 °C water mist at 9 MPa is more effective in extinguishing n-heptane fire. The flame extinction time is about 10 s, which is more than 40 s higher than that of cold water.

An Analytical Study on Performance of Soyabean Crop in India

Abstract: Agriculture is backbone of the Indian Economy. Agriculture sector provides food security for the entire population and provide raw material to many agro industries. Oilseed crops are the second most important determinant of agricultural economy, next only to cereals within the segment of field crops. India is one of the largest producers of oilseeds in the world and occupies an important position in the Indian agricultural economy. Soybean contributes significantly to the Indian edible oil pool. Presently soybean contributes 43 % to the total oilseeds and 25% to the total oil production in the country. Currently, India ranks fourth in respect to production of soybean in the world. In the present paper, an analytical study has been taken up for the production trend and growth rate by using three years moving average for area sown, productivity and production for Soyabean crop. State-wise analysis has also been carried out for Soyabean producing States. The future projection for production and productivity have also been worked out. In view of the importance of this sector for ensuring inclusive growth and the need to achieve self-sufficiency in oilseeds production, key challenges faced by the edible oils sector and the strategy to address them are also spelled out.

Correlation Investigation of Wind Turbine Multiple Operating Parameters Based on SCADA Data

The primary wind turbines’ in-service performance evaluation method is mining and analyzing the SCADA data. However, there are complex mathematical and physical relationships between multiple operating parameters, and so far, there is a lack of systematic understanding. To solve this issue, the distribution of wind turbines’ operating parameters was first analyzed according to the characteristics of the energy flow of wind turbines. Then, the correlation calculation was performed using the Spearman correlation coefficient method based on the minute-level data and second-level data. According to the numerical characteristics of the nacelle vibration acceleration, the data preprocessing technology sliding window maximum (SWM) was proposed during the calculation. In addition, taking temperature correlation as an example, two-dimensional scatter (including single-valued scatter) and three-dimensional scatter features were combined with numerical analysis and physical mechanism analysis to understand the correlation characteristics better. On this basis, a quantitative description model of the temperature characteristics of the gearbox oil pool was constructed. Through this research work, the complex mathematical and physical relationships among the multi-parameters of the wind turbines were comprehensively obtained, which provides data and theoretical support for the design, operation, and maintenance.

Boiling of water droplet in glass–oil–water multiphase system

Boiling a volatile droplet in non-volatile liquid is complex because of various interface interactions in a solid–liquid–liquid system. Previous studies have reported explosive boiling and attributed this phenomenon to heterogeneous nucleation due to solid–liquid contact. In this study, we investigated the boiling of an approximately 2 mm-diameter water droplet in a silicon oil pool inside a glass container. Two transition temperatures were observed: 122.5 °C (for the transition from evaporation to boiling) and 160.0 °C (for the transition from the bubble growth on the oil side to that on both the oil and water sides). Moreover, four boiling modes were identified: evaporation (E), boiling in water (BIW: bubble nucleation at the glass–water interface and growth inside a drop), boiling in oil (BIO: bubble nucleation at the oil–water interface and growth in oil), and boiling in oil and water (BIOW: bubble nucleation at the oil–water interface and growth in oil and water). For the first time, boiling bifurcation was observed for drop boiling in a three-phase system. For the oil temperature (Tb) in the range 122.5–160.0 °C, the boiling mode switches between BIW and BIO. In contrast, for Tb exceeding 160.0 °C, either BIW or BIOW occurs. This bifurcation occurs because droplets prefer minimum activation energy between that for the bubble nucleation at the solid–water interface and that for the bubble nucleation at the oil–water interface. Interfacial instabilities were analyzed to explain why BIOW was more violent than BIW. This work presents a comprehensive understanding of droplet boiling in a three-phase system.

MODELING HYDROCARBON GENERATION IN ANAMBRA BASIN, SOUTHEASTERN NIGERIA: IMPLICATIONS ON HYDROCARBON PROSPECTIVITY.

The Anambra Basin contains oil and gas producing reservoirs in the southeastern part of Nigeria. Two-dimensional (2-D) modeling, using data from three (3) exploration wells has been carried out to assess the maturity, timing, and distribution of hydrocarbon generation in the Anambra Basin. This current study focuses on two sources in Anambra Basin namely; Coniacian Agwu and Nkporo source rocks. The results of models generated indicate that the onset of hydrocarbon generation from Awgu source rock started in the area of deepest subsidence during the late Campanian (77.30Ma). Awgu source rock in the model has a present-day transformation ratio of about 60-65%. This range indicates that the Awgu source rock has sufficient generation for hydrocarbon expulsion to occur. Nkporo source rock was equally observed to have capacity for hydrocarbon generation, but the generation was insufficient for expulsion because it has lower transformation ratio (<10%). Migrated hydrocarbon from the Coniacian Awgu source rock must have accumulated as oil and gas pools within the Coniacian Agbani and upper Campanian Owelli Sandstone. The discovery of gas in the Coniacian Agbani sandstone of Amansiodo-1, Akukwa-2, and Nzam-1 wells indicates the existence of petroleum traps in Cretaceous beds of the Anambra Basin. Keywords: Two dimensional modelling, Hydrocarbon generation and expulsion, Anambra basin, Transformation ratio, Awgu and Nkporo shales ,

Geological trends of occurrence of heavy oil pools in north-eastern part of Timan-Pechora Province

Geological trends of occurrence of heavy oil pools in north-eastern part of Timan-Pechora Province

Construction of geological and mathematical models for modeling the oil pool of the Kenkiyak deposit

Geological and mathematical models of the oil reservoir of the post-salt Kenkiyak field have been investigated and built. 6 types of geological models have been proposed, and on the basis of these models, mathematical models of oil deposits have been developed. Geological models are built on the basis of research results, taking into account the requirements of regulating the development of the Kenkiyak field, the geological characteristics of the field and the rate of operation. The mathematical model is based on the basic Darcy equations and includes equations for conservation of mass and energy, equations for limiting mass and oil saturation. The issues of modeling and determination of the relative permeability at the end point are studied, the results of determining the parameters of the relative permeability of different formations at normal and high temperatures are presented. The results of identification of parameters of mathematical models are considered.

Ultimate potentials of old oil pools: A quantitative range

Ultimate potentials of old oil pools: A quantitative range

Formation mechanisms, potentials and exploration practices of large lithologic gas reservoirs in and around an intracratonic rift: Taking the Sinian—Cambrian of Sichuan Basin as an example

By examining structures, sediments, reservoirs and accumulation assemblages in the Deyang—Anyue rift and its surrounding area, four new understandings are obtained. First, during the initiation period of Deyang—Anyue rift, multiple groups of faults developed in the rift due to the effect of tensile force, bringing about multiple mound and shoal belts controlled by horsts in the second member of the Sinian Dengying Formation; in the development stage of the rift, the boundary faults of the rift controlled the development of mound and shoal belts at the platform margin in the fourth member of Dengying Formation; during the shrinkage period of the rift, platform margin grain shoals of the Cambrian Canglangpu Formation developed in the rift margin. Second, four sets of large-scale mound and shoal reservoirs in the second member of Dengying Formation, the fourth member of Dengying Formation, Canglangpu Formation and Longwangmiao Formation overlap with several sets of source rocks such as Qiongzhusi Formation source rocks and Dengying Formation argillaceous limestone or dolomite developed inside and outside the rift, forming good source-reservoir-cap rock combinations; the sealing of tight rock layers in the lateral and updip direction results in the formation model of large lithologic gas reservoirs of oil pool before gas, continuous charging and independent preservation of each gas reservoir. Third, six favorable exploration zones of large-scale lithologic gas reservoirs have been sorted out through comprehensive evaluation, namely, mound and shoal complex controlled by horsts in the northern part of the rift in the second member of Dengying Formation, isolated karst mound and shoal complex of the fourth member of Dengying Formation in the south of the rift, the superimposed area of multi-stage platform margin mounds and shoals of the second and fourth members of Dengying Formation and Canglangpu Formation in the north slope area, the platform margin mounds and shoals of the second and fourth members of Dengying Formation in the west side of the rift, the platform margin mound and shoal bodies of the fourth member of Dengying Formation in the south slope area, etc. Fourth, Well Pengtan-1 drilled on the mound and shoal complex controlled by horsts of the second member of Dengying Formation in the rift and Well Jiaotan-1 drilled on the platform margin mound and shoal complex of the North Slope have obtained high-yield gas flows in multiple target layers, marking the discovery of a new gas province with reserves of (2—3)×1012 m3. This has proved the huge exploration potential of large lithologic gas reservoir group related to intracratonic rift.

Experimental Study on Combustion Characteristics of Transformer Oil Pool Fire with Different Scales

To study the combustion characteristics of transformer oil pool fire with different sizes, transformer oil pool fire experiments with diameters of 40cm, 50cm, and 60cm are carried out to analyze the evolution laws of flame height, fire plume temperature, and oil temperature of oil pool fire with different diameters. The results show that the ignition process of the transformer oil pool can be divided into three typical stages: initial growth stage, full development stage, and extinguished stage. According to the characteristics of combustion rate and flame height, the full development stage is subdivided into the stable combustion stage and boiling combustion stage. The flame height of the boiling combustion stage is about 1.1 times higher than that of the stable combustion stage. With the increase of diameter, the range of intermittent flame area of oil pool fire with three diameters increases by 1.2 times. The heat transfer analysis of the full development stage shows that the oil temperature presents the phenomenon of temperature stratification. There is a boiling layer below the liquid level. Its temperature is about 330 °C and its thickness is about 2.3 mm. The oil temperature under the boiling layer decreases in a gradient, and the boiling layer thickness and temperature have no significant correlation with the oil pool diameter.

Study on the effect of mist flux on water mist fire extinguishing

A series of combustion experiments were carried out by varying the pressure of water mist and the power of the fire source in order to quantitatively study the fire-extinguishing conditions of water mist. The main characteristics of an oil pool fire under the action of water mist are revealed through the analysis of experimental parameters, and a fire extinguishing model is established. The results showed that the thick flammable vapor layer on the oil surface is the source of water mist-induced flame expansion. Besides that, the splashing of oil droplets is one of the reasons for the flame's enhancement. After simplifying the combustion model, the heat and mass transfer approach was utilized to quantitatively study the water mist flux model for fire suppression. When the thrust ratio of fire versus spray (α) exceeds 5, the plume thrust has a significant impact on the water mist droplet trajectory, and the fire extinguishing fails. In other words, the water mist's cooling action is the primary mechanism for putting out the pool fire. The failure to extinguish the fire was mostly due to the mist flux being insufficient to absorb enough heat from the fuel surface to break the combustion equilibrium conditions.

Extinguishment of a transformer fire with a long projection water mist system

When large oil-immersed power transformer fire happens, scenarios such as bushing explosion, oil pool fire, oil spray fire and oil flowing fire are commonly observed. As the nozzles of current water mist or sprinkler system are arranged in the fire region, they are at risk of damage during the explosion or under high temperature. This paper presents a long projection water mist technique based on axial flow inducing to effectively extinguish the fire at far distance. The droplet size, spray density, and effective spray distance were characterized via Laser diffraction technique, water collection method and laser distance measurement. Fire extinguishment tests were conducted through setting up a full-scale 800 kV converter transformer model to verify its capability. The results indicate that the proposed system can extinguish the 800 kV converter transformer fire within dozens of seconds, due to its long spray distance, small droplet size, and large spray density. This study will provide a new method for water mist generation and references for system design for large transformer fire or oil fire extinguishment in open space.

Excellent source rocks found along the margin of a large lacustrine basin: Case study from the Ordos Basin, China

Whether the Chang 6 oil pools of the Triassic Yanchang Formation in the Ansai-Yanchang (AY) oil province on the Yishan slope of the Ordos Basin formed from near source rock or far source rock has long been debated. An understanding of the source rock's position will impact the formation mode and distribution of accumulations in this area. Based on the geochemical data of the Chang 7 source rock in six wells and 18 crude oil samples, the geochemical characteristics of Chang 7 source rock and its relationship with Chang 6 crude oil were studied. There are two types of source rocks, namely, black shales and dark mudstones, present in the AY area. The gross thickness of the Chang 7 black shale is 3.0–19.7 m, with a distribution area of 5500 km2. It has an average total organic carbon (TOC) content of 3.34%, with a chloroform bitumen “A" content of 0.512%, indicating good to excellent source rock potential. The kerogen assessment with core samples shows mixed type I-II1, and has reached peak oil generation, maximum pyrolysis temperatures (Tmax) ranging from 445 to 458 °C. In contrast, the average TOC content of the dark mudstone in Chang 7 is 0.91%, chloroform bitumen “A” is 0.079%, the main type of kerogen is type II2-II1, and Tmax varying from 446 to 461 °C, indicating only fair source rock potential overall. The Chang 7 source rocks in the AY area have a gammacerane index of 0.07–0.38, with an average value of 0.21, which reflects a low-salinity fresh to brackish water environment. The relative abundances of C27, C28, and C29 steranes are 29.7%, 23.1% and 47.2%, respectively, indicating that terrestrial higher plants and aquatic organisms provide similar contribution in the Chang 7 source rocks. Oils produced from the AY area of the Chang 6 member have similar geochemical signatures, but are significantly different from the Chang 6 crude oils in the Daozhen (DZ) area of Ganquan County and the Huaishuzhuang (HSZ) area of Fuxian County, which are located in the center of the lacustrine basin. They differ in terms of the maturity of the oil samples and the microscale composition of the parent material type. The closer the wells are to the center of the lacustrine basin, the higher the maturity of the source rock and the greater the contribution of aquatic organisms. The variation of carbon isotopic composition of Chang 6 crude oil in AY area is consistent with that of Chang 7 shale locally, but opposite to that of Chang 6 crude oil in DZ area. The ratios of nC21-/nC22+, tricyclic terpane/hopane and C29 sterane ββ/(ββ+αα) biomarker parameters of Chang 6 crude oils in AY area are similar to those of Chang 7 shale in local area, but deviate from those of DZ and HSZ area. These data results reveal that the Chang 6 crude oils in the AY oil province are dominated by the local Chang 7 excellent source rocks rather than by the long-distance migration of oils from the basin center.

Creation story

He makes the light and the primeval oceans and the rapturous Word, but I have the dirtthe ground the chthonic underbelly and sustenance of all. I have the jewel-toned beetles and cavern cathedrals and the slick blesmols. The translucent jellyfish and the elegant otherworldly bats. The velutinous darkness I see when I close my eyes and look out is what I create—that moment of descending into something unknownwith limitless possibility. Black calla lilies and thick root webs and lithe olms and the young coyotes with protruding ribcages.Before I sculpt the earthand the atmosphere tooI try to enjoy this night and remember my sliver of time before the labor of creation. The time of loving and crying and walking through snow floating down like tiny newborn stars. The time of waking up to the bright marmalade sunrise shining through the bathroom window and whispering to the daytime moon. I was a lover eating rabbit stewwondering how I could rupture so violentlyso completelyand still move forward through time.The old time of unknowing, of not knowing the unknown.On the first dayI made the starling and then let its feathers become the centerpiece of the highest worldglittering with iridescent specklesletting the undertones of violet and turquoise shine through.This(I thought)is the skythe world's favorite quilt: the starling as firmament.I rest tonight and think about my large-souled dayslike when my father taught me how to fishor when I picked bucketfuls of fresh strawberries in springor flew through gilded air on a bicycle in June.It is no coincidence thenthat the words soil and soul are nearly identical sonic twinsseeing as the layers of my soullike a stratigraphyread certain scales of timeexperienceand remember past lives fossilized in the sentient sensual sediment of the body. The strata run horizontal like long thin snakes with writhing bellies underneath my skinvarying in widthas some strands of time are denser with memory than others.This is where I will begin and endin remembering these moments of unknown beauty and quiet grit.Underneath the soul's many mineral depositsthe liquid core sends a pulse through the bodyspilling blood through an ecosystem of veins. Here, at the heart, I remember my shamewhich smells like cinnamon—sharp and harsh and cathartic. Memory may not be a realitybut it bends and melts into worlds both known and unknownpreserved in our salubrious soils.I recall that I am a world unto myselfslowly dissolving untilat last at last my burning center is exposedand burns hot and shimmers right before it erupts into a thousand shining pieces that float like meteors in an unknown reservoir.On the second dayI will make the dirta luscious loam with a dense liquid heart that beats and writhes and fuels the world forward. It is the origin from which everything else will flower and grow without my help, alone and unabated. I will make the ground strong and softfull of sculptures and sepulchres and pools of oil and iron. I will create sandstone red as summer cherries and rough as a man's stubble, like thistles.Worldmaking is an act of time grace and pain anger and patience love. It is a birthing. I trust my body and create the underworld the underneath the subterranean. The clay the silt the dirt the sand. Within the soil of the world is where the fleshy self iswhere secrets are whispered and sung. All things are taken into the soft world of the earth in a returninga homecoming that invites new life through transforming death. It is where things are made radical and rejuvenated and why mud spread over the eyes gives sight. A body placed into the ground is born anewmade supple through time and slithering annelids.

Petroleum system modelling of Pelotas basin, offshore Brazil using 2D basin modelling approach

The ongoing exploration activities at the Pelotas basin of Brazil uncover some missing gaps in the existing wells for hydrocarbon accumulation prediction. Therefore, there is a need to further investigate the petroleum system of the basin, especially the organic facies, variations and distributions of the effectiveness of potential source rock. The adjacent basin, Santos basin is currently producing oil and gas fields will be used as the analogs to the Pelotas Basin. The aims of this research are to justify the presence of geological elements and processes of the petroleum system of the Pelotas Basin and to evaluate the potential of hydrocarbon prospectivity for exploration and exploitation of the basin. Two – dimensional basin modelling using TemisFlow will be used in this study. Hydrocarbon generation from the Turonian and Ypresian to Bartonian source rock started during Late Eocene. Visible Hydrocarbon migration can be seen from the Hydrocarbon saturation model. Hydrocarbon migration for Turonian source rock occurred during Early Miocene while for Ypresian to Bartonian, hydrocarbon migrate during Middle Miocene. Peak hydrocarbon expulsion reached during Middle Miocene for Turonian source rock and Ypresian to Bartonian source rock. Based on modelling result, hydrocarbon accumulation can be seen in Upper slope Early Miocene Sandstone, Early Miocene turbiditic sandstone and Early Oligocene turbiditic sandstone. Hydrocarbon composition in Early Miocene turbiditic sandstone and Upper Oligocene sandstone is mainly hydrocarbon liquid while for Early Miocene sandstone, the hydrocarbon composition is mix of hydrocarbon liquid and gas. Based on the prediction of source facies distribution, thermal maturity assessment, and migration and trapping mechanism, the oil and gas pool can be proposed for the future exploration and exploitation in the Pelotas Basin, offshore Brazil.

Ресурсный потенциал гряды Чернышева (Тимано-Печорский бассейн) в контексте новых данных о строении и продуктивности соленосных надвиговых поясов

The salt bearing thrust belts are among the most prolific petroleum provinces in the world, including the fold belts flanking the Persian Gulf Basin, the Tarim Basin, the Terek-Sunzha Zone of the Eastern PreCaucasus etc. They are characterized by peculiar structural styles of deformation, large oil and gas pool sizes, significant flow rates. The Chernyshev Swell is among prospective salt bearing thrust belts. It is located in the Cis-Uralian part of the Timan Pechora Basin. Several exploration wells have been drilled in the area so far failed to deliver the anticipated oil and gas deposits. Post mortem study indicated that the main reason for the past failures was the mismatch between the complexities of the geological settings and the used exploration technologies. Integrated study of the area, conducted by the North Uralian Petroleum Company, using modern technologies, including 3D seismic surveying and magnetotelluric sounding, has enabled a far better understanding of this area’s structure and petroleum habitat. It is shown that high petroleum potential is attributed to the transition zone between the Chernyshev Swell and the Kosyu Rogov Foredeep Basin. This study indicated that the area of the Povarnitsa High is of priority interest for explration. This area provides supplementary opportunities in addition to the commercialization of the petroleum exploration potential. It includes production of rare earth and metals in brine of the evaporate deposits. The subsalt reservoirs of the Chernyshev Swell could be used for the storage of gas and CO2 sequestration. Integrated development of the resource potential of the Povarnitsa High may become a key driver of the economic development of the north-eastern part of the Republic of Komi.

The Emission Characteristics of Pollutants from Thermal Desorption of Soil Contaminated by Transformer Oil

In order to reduce pollutant emission from substation fires into the soil environment, developing technology to remove pollutants in soil after substation fires is necessary. Among the soil remediation technologies, thermal desorption has been proven to be an effective soil remediation method. In this paper, the effects of thermal desorption temperature and atmosphere on the releasing characteristics of pollutants in the soil polluted by waste oil in the accident oil pool in the substation were examined. The results showed that when the thermal desorption temperature was 500 °C, a large number of macromolecular organics decompose from the solid phase and change into long-chain alkanes and macromolecular acids under pure N2 atmosphere. When the thermal desorption temperature was higher than 500 °C the pollutants in the soil were further decomposed into small molecular organics. In addition, the organics were transformed to CO2, SO2, NOx, and CO under 20% O2/N2 atmosphere when the temperature was above 500 °C.